Well, I just did it -- I published my first page in a web application using the Domino framework that doesn't let Domino automatically set the DOCTYPE (I'm using XHTML 1.0 Strict, by the way). Here's to good things to come!
Only taken me a year to get here (mostly because, with a framework of this size, I had to be absolutely sure that this kind of thing would work).
Well, fark that -- I'm using a DOCTYPE, but it's got to be HTML 4.01 Transitional. Apparently, anything higher than that and IE starts having little fits here and there while it's trying to render things. Figures.